Pooling of fluid in a patient's limbs and consequent swelling of the limb or limbs is a deleterious condition which can arise from a variety of causations. For example, patients who are bedridden for prolonged periods may experience pooling of fluid in their limbs. As another example, congenital or secondary lymphedema, i.e., stasis of lymphatic fluid in an extremity of a patient, causes painful, unsightly, and ultimately dangerous swelling of the afflicted limb.
It has been recognized that swelling of limbs can be treated by applying pressure to the limb to force static fluid in the limb toward the trunk of the patient's body. For example, U.S. Pat. No. 4,762,121 ("the '121 patent") discloses a massaging sleeve that is formed with a plurality of transversely oriented cells, and an inflatable fluid bag is disposed in each of the cells. Each fluid bag includes a fluid line connector that extends through a hole formed in the associated cell, and the fluid line connectors can be connected to respective fluid lines. To treat the patient, the sleeve is wrapped around a patient's limb, and the fluid bags are then filled with fluid to compress the limb and force fluid out of the limb toward the trunk of the body.
While effective for its intended purpose, the device disclosed in the '121 patent suffers from several inherent drawbacks. For instance, to facilitate removing a damaged bag and positioning a new bag in the cell, one side edge of each cell is open, but as recognized by the present invention it can be cumbersome and difficult to install a replacement fluid bag in a cell having only one open side edge. Another drawback to the '121 device is that the fluid line connectors extend outside the sleeve, and consequently can be unintentionally disengaged from their respective fluid lines by the patient during therapy. The present invention recognizes that a compression sleeve can be provided which overcomes both of these prior art problems.
In addition to particular compression sleeve designs, prior art devices have also included various apparatus for inflating a compression sleeve. Representative of such devices is the apparatus disclosed in U.S. Pat. No. 4,013,069 ("the '069 patent") for a sequential intermittent compression device for use in an operating room. As disclosed in the '069 patent, a pump pressurizes several fluid lines which lead to respective cells in a compression sleeve. Orifices are installed in the lines to control the rate of pressure increase in each cell (or group of cells), and the time periods between inflation of adjacent groups of cells is adjustably controlled by means of a pneumatically-operated timer. Indeed, because the '069 patented apparatus is intended for use in an operating room, it teaches the use of pneumatically-operated control components, to avoid potential sparking which could arise, according to the '069 patent, from the use of electrically-operated control components.
Furthermore, the apparatus disclosed in the '069 patent purportedly can pressurize each group of cells to a pressure that can be different from the pressure of the other cell groups, thereby establishing a pressure gradient along the limb being treated. As disclosed in the '069 patent, however, all cells are ultimately in fluid communication with each other during the inflation cycle. Consequently, while the rate of pressurization of the various cell groups can be individually established by selecting appropriately sized orifices, it is unclear that the final pressures in each group can in fact differ from each other, given that the final pressure in each cell group must eventually equalize with the pressures in the other cell groups.
Additionally, while the '069 patent discloses a means for establishing a pressure rise time for each cell group which is different from the pressure rise times of the other cell groups, the rise time of each cell group cannot be dynamically controlled. Instead, to vary the pressure rise time of a group of cells, the orifice leading to the particular cell group must be removed and replaced with a differently-sized orifice. Such a procedure is time-consuming and cumbersome, and ordinarily must be performed by a trained technician.
Further, the final pressure in each cell group of the '069 patented apparatus cannot be varied or dynamically established. Moreover, while it is possible to vary the time between filling of successive cell groups, the inflation sequence itself cannot be dynamically varied.
Thus, as a practical matter, the apparatus disclosed in the '069 patent, like other prior art devices, offers a relatively limited number of therapy options. As recognized by the present invention, however, it is desirable that a compression therapy apparatus provide a large number of therapy options to ensure the availability of a compression therapy program which is tailored to the needs and peculiar physiological requirements of the particular patient being treated. Further, the present invention recognizes that it would be advantageous to provide a means for easily and dynamically establishing the variables of a particular therapy program, as dictated by physiological changes in the patient.
Accordingly, it is an object of the present invention to provide an apparatus and method for compression therapy which can undertake a variety of compression therapy programs. Another object of the present invention is to provide an apparatus and method for compression therapy that provides for dynamically controlling the parameters of the compression therapy. Still another object of the present invention is to provide a compression sleeve for treating edema-induced swelling of a patient's limb which is easy to use and cost-effective to maintain and manufacture.